1. Field of the Invention
The present invention relates to a method for establishing a call connection in a wireless terminal, and more particularly to a method for establishing a call connection in a wireless terminal, which can make a call connection using one line number when a call connection fails through another line number in a wireless terminal subscribing to a service in which the portable terminal uses two line numbers.
2. Description of the Related Art
An Alternative Line Service (ALS) is one of the available additional services in a global system for mobile communications (GSM) scheme, and uses a general voice call while providing two line numbers to a user so that the user can use communication services through two lines.
The ALS technology selects and uses any one line number of the two line numbers, and uses one International Mobile Subscriber Identity so as to identify two Mobile Subscriber Integrated Service Digital Numbers (MSISDN) and the respective subscriptions.
In the case where a subscriber identity module (SIM) card supports Common Personal Handset Specification (CPHS), the SIM card is used with reference to Dynamic_flag 1 and 2 in order to use the ALS. If the Dynamic_flag 1 is “zero”, the SIM card is used through a primary line number. On the other hand, if the Dynamic_flag 1 is “one”, the SIM card is used through an auxiliary line number. The SIM card generally has PIN 1 used for setting a password, and PIN 2 used for changing the value of a certain security. It is possible to control the security against the change of the number of the ALS using the value of the PIN 2.
Furthermore, a separate ring tone can be assigned to each of the two numbers of the ALS.
The user of the wireless terminal who subscribes to the ALS described above can experience failure of call requests, which are frequently caused by the limited nature of resources due to a rapid increasing of wireless terminals. In the above-mentioned case, even though technology is advancing in order to solve the call request problem, the user is sometimes burdened because of the need to subscribe to certain services with payment of expensive monthly charges.